The invention had the object of finding novel compounds having valuable properties, in particular those which can be used for the preparation of medicaments.
The present invention relates to compounds and to the use of compounds in which the inhibition, regulation and/or modulation of signal transduction by kinases, in particular TGF-beta receptor kinases, plays a role, furthermore to pharmaceutical compositions which comprise these compounds, and to the use of the compounds for the treatment of kinase-induced diseases.
Transforming growth factor beta is the prototype of the TGF-beta superfamily, a family of highly preserved, pleiotrophic growth factors, which carry out important functions both during embryo development and also in the adult organism. In mammals, three isoforms of TGF-beta (TGF-beta 1, 2 and 3) have been identified, TGF-beta 1 being the commonest isoform (Kingsley (1994) Genes Dev 8:133-146). TGF-beta 3 is expressed, for example, only in mesenchymal cells, whereas TGF-beta 1 is found in mesenchymal and epithelial cells. TGF-beta is synthesized as pre-proprotein and is released in inactive form into the extracellular matrix (Derynck (1985) Nature 316: 701-705; Bottinger (1996) PNAS 93: 5877-5882). Besides the proregion cleaved off, which is also known as latency associated peptide (LAP) and remains associated with the mature region, one of the 4 isoforms of the latent TGF-beta binding proteins (LTBP 1-4) may also be bonded to TGF-beta (Gentry (1988) Mol Cell Biol 8: 4162-4168, Munger (1997) Kindey Int 51: 1376-1382). The activation of the inactive complex that is necessary for the development of the biological action of TGF-beta has not yet been clarified in full. However, proteolytic processing, for example by plasmin, plasma transglutaminase or thrombospondin, is certainly necessary (Munger (1997) Kindey Int 51: 1376-1382). The activated ligand TGF-beta mediates its biological action via three TGF-beta receptors on the membrane, the ubiquitously expressed type I and type II receptors and the type III receptors betaglycan and endoglin, the latter only being expressed in endothelial cells (Gougos (1990) J Biol Chem 264: 8361-8364, Loeps-Casillas (1994) J Cell Biol 124:557-568). Both type III TGF-beta receptors lack an intracellular kinase domain which facilitates signal transmission into the cell. Since the type III TGF-beta receptors bind all three TGF-beta isoforms with high affinity and type II TGF-beta receptor also has higher affinity for ligands bonded to type III receptor, the biological function is thought to consist in regulation of the availability of the ligands for type I and type II TGF-beta receptors (Lastres (1996) J Cell Biol 133:1109-1121; Lopes-Casillas (1993) Cell 73: 1435-1344). The structurally closely related type I and type II receptors have a serine/threonine kinase domain, which is responsible for signal transmission, in the cytoplasmatic region. Type II TGF-beta receptor binds TGF-beta, after which the type I TGF-beta receptor is recruited to this signal-transmitting complex. The serine/threonine kinase domain of the type II receptor is constitutively active and is able to phosphorylate seryl radicals in this complex in the so-called GS domain of the type I receptor. This phosphorylation activates the kinase of the type I receptor, which is now itself able to phosphorylate intracellular signal mediators, the SMAD proteins, and thus initiates intracellular signal transmission (summarized in Derynck (1997) Biochim Biophys Acta 1333: F105-F150).
The proteins of the SMAD family serve as substrates for all TGF-beta family receptor kinases. To date, 8 SMAD proteins have been identified, which can be divided into 3 groups: (1) receptor-associated SMADs (R-SMADs) are direct substrates of the TGF-β receptor kinases (SMAD1, 2, 3, 5, 8); (2) co-SMADs, which associate with the R-Smads during the signal cascade (SMAD4); and (3) inhibitory SMADs (SMAD6, 7), which inhibit the activity of the above-mentioned SMAD proteins. Of the various R-SMADs, SMAD2 and SMAD3 are the TGF-beta-specific signal mediators. In the TGF-beta signal cascade, SMAD2/SMAD3 are thus phosphorylated by the type I TGF-beta receptor, enabling them to associate with SMAD4. The resultant complex of SMAD2/SMAD3 and SMAD4 can now be translocated into the cell nucleus, where it can initiate the transcription of the TGF-beta-regulated genes directly or via other proteins (summarized in Itoh (2000) Eur J Biochem 267: 6954-6967; Shi (2003) Cell 113: 685-700).
The spectrum of the functions of TGF-beta is wide-ranging and dependent on cell type and differentiation status (Roberts (1990) Handbook of Experimental Pharmacology: 419-472). The cellular functions which are influenced by TGF-beta include: apoptosis, proliferation, differentiation, mobility and cell adhesion. Accordingly, TGF-beta plays an important role in a very wide variety of biological processes. During embryo development, it is expressed at sites of morphogenesis and in particular in areas with epithelial-mesenchymal interaction, where it induces important differentiation processes (Pelton (1991) J Cell Biol 115:1091-1105). TGF-beta also carries out a key function in the self-renewal and maintenance of an undifferentiated state of stem cells (Mishra (2005) Science 310: 68-71). In addition, TGF-beta also fulfils important functions in the regulation of the immune system. It generally has an immunosuppressive action, since it inhibits, inter alia, the proliferation of lymphocytes and restricts the activity of tissue macrophages. TGF-beta thus allows inflammatory reactions to subside again and thus helps to prevent excessive immune reactions (Bogdan (1993) Ann NY Acad Sci 685: 713-739, summarized in Letterio (1998) Annu Rev Immunol 16: 137-161). Another function of TGF-beta is regulation of cell proliferation. TGF-beta inhibits the growth of cells of endothelial, epithelial and haematopoietic origin, but promotes the growth of cells of mesenchymal origin (Tucker (1984) Science 226:705-707, Shipley (1986) Cancer Res 46:2068-2071, Shipley (1985) PNAS 82: 4147-4151). A further important function of TGF-beta is regulation of cellular adhesion and cell-cell interactions. TGF-beta promotes the build-up of the extracellular matrix by induction of proteins of the extracellular matrix, such as, for example, fibronectin and collagen. In addition, TGF-beta reduces the expression of matrix-degrading metalloproteases and inhibitors of metalloproteases (Roberts (1990) Ann NY Acad Sci 580: 225-232; lgnotz (1986) J Biol Chem 261: 4337-4345; Overall (1989) J Biol Chem 264: 1860-1869); Edwards (1987) EMBO J 6: 1899-1904).
The broad spectrum of action of TGF-beta implies that TGF-beta plays an important role in many physiological situations, such as wound healing, and in pathological processes, such as cancer and fibrosis.
TGF-beta is one of the key growth factors in wound healing (summarized in O'Kane (1997) Int J Biochem Cell Biol 29: 79-89). During the granulation phase, TGF-beta is released from blood platelets at the site of injury. TGF-beta then regulates its own production in macrophages and induces the secretion of other growth factors, for example by monocytes. The most important functions during wound healing include stimulation of chemotaxis of inflammatory cells, the synthesis of extracellular matrix and regulation of the proliferation, differentiation and gene expression of all important cell types involved in the wound-healing process.
Under pathological conditions, these TGF-beta-mediated effects, in particular the regulation of the production of extracellular matrix (ECM), can result in fibrosis or scars in the skin (Border (1994) N Engl J Med 331:1286-1292).
For the fibrotic diseases, diabetic nephropathy and glomeronephritis, it has been shown that TGF-beta promotes renal cell hypertrophy and pathogenic accumulation of the extracellular matrix. Interruption of the TGF-beta signaling pathway by treatment with anti-TGF-beta antibodies prevents expansion of the mesangial matrix, progressive reduction in kidney function and reduces established lesions of diabetic glomerulopathy in diabetic animals (Border (1990) 346: 371-374, Yu (2004) Kindney Int 66: 1774-1784, Fukasawah (2004) Kindney Int 65: 63-74, Sharma (1996) Diabetes 45: 522-530).
TGF-beta also plays an important role in liver fibrosis. The activation, essential for the development of liver fibrosis, of the hepatic stellate cells to give myofibroblasts, the main producer of the extracellular matrix in the course of the development of liver cirrhosis, is stimulated by TGF-beta. It has likewise been shown here that interruption of the TGF-beta signaling pathway reduces fibrosis in experimental models (Yata (2002) Hepatology 35:1022-1030; Arias (2003) BMC Gastroenterol 3:29).
TGF-beta also takes on a key function in the formation of cancer (summarized in Derynck (2001) Nature Genetics: 29: 117-129; Elliott (2005) J Clin One 23: 2078-2093). At early stages of the development of cancer, TGF-beta counters the formation of cancer. This tumor-suppressant action is based principally on the ability of TGF-beta to inhibit the division of epithelial cells. By contrast, TGF-beta promotes cancer growth and the formation of metastases at late tumor stages. This can be attributed to the fact that most epithelial tumors develop a resistance to the growth-inhibiting action of TGF-beta, and TGF-beta simultaneously supports growth of the cancer cells via other mechanisms. These mechanisms include promotion of angiogenesis, the immunosuppressant action, which supports tumor cells in avoiding the control function of the immune system (immunosurveillance), and promotion of invasiveness and the formation of metastases. The formation of an invasive phenotype of the tumor cells is a principal prerequisite for the formation of metastases. TGF-beta promotes this process through its ability to regulate cellular adhesion, motility and the formation of the extracellular matrix. Furthermore, TGF-beta induces the transition from an epithelial phenotype of the cell to the invasive mesenchymal phenotype (epithelial mesenchymal transition=EMT). The important role played by TGF-beta in the promotion of cancer growth is also demonstrated by investigations which show a correlation between strong TGF-beta expression and a poor prognosis. Increased TGF-beta level has been found, inter alia, in patients with prostate, breast, intestinal and lung cancer (Wikström (1998) Prostate 37: 19-29; Hasegawa (2001) Cancer 91: 964-971; Friedman (1995), Cancer Epidemiol Biomarkers Prev. 4:549-54).
Owing to the cancer-promoting actions of TGF-beta described above, inhibition of the TGF-beta signaling pathway, for example via inhibition of the TGF-beta type I receptor, is a possible therapeutic concept. It has been shown in numerous preclinical trials that interruption of the TGF-beta signaling pathway does indeed inhibit cancer growth. Thus, treatment with soluble TGF-beta type II receptor reduces the formation of metastases in transgenic mice, which develop invasive breast cancer in the course of time (Muraoka (2002) J Clin Invest 109: 1551-1559, Yang (2002) J Clin Invest 109: 1607-1615).
Tumor cell lines which express a defective TGF-beta type II receptor exhibit reduced tumor and metastatic growth (Oft (1998) Curr Biol 8: 1243-1252, McEachern (2001) Int J Cancer 91:76-82, Yin (1999) J Clin Invest 103: 197-206).
Conditions “characterized by enhanced TGF-β activity” include those in which TGF-β synthesis is stimulated so that TGF-β is present at increased levels or in which TGF-β latent protein is undesirably activated or converted to active TGF-β protein or in which TGF-β receptors are upregulated or in which the TGF-β protein shows enhanced binding to cells or extracellular matrix in the location of the disease. Thus, in either case “enhanced activity” refers to any condition in which the biological activity of TGF-β is undesirably high, regardless of the cause.
A number of diseases have been associated with TGF-β1 overproduction.
Inhibitors of TGF-β intracellular signaling pathway are useful treatments for fibroproliferative diseases. Specifically, fibroproliferative diseases include kidney disorders associated with unregulated TGF-β activity and excessive fibrosis including glomerulonephritis (GN), such as mesangial proliferative GN, immune GN, and crescentic GN. Other renal conditions include diabetic nephropathy, renal interstitial fibrosis, renal fibrosis in transplant patients receiving cyclosporin, and HIV-associated nephropathy. Collagen vascular disorders include progressive systemic sclerosis, polymyositis, sclerorma, dermatomyositis, eosinophilic fascitis, morphea, or those associated with the occurrence of Raynaud's syndrome. Lung fibroses resulting from excessive TGF-β activity include adult respiratory distress syndrome, idiopathic pulmonary fibrosis, and interstitial pulmonary fibrosis often associated with autoimmune disorders, such as systemic lupus erythematosus and sclerorma, chemical contact, or allergies. Another autoimmune disorder associated with fibroproliferative characteristics is rheumatoid arthritis.
Eye diseases associated with a fibroproliferative condition include retinal reattachment surgery accompanying proliferative vitreoretinopathy, cataract extraction with intraocular lens implantation, and post-glaucoma drainage surgery are associated with TGF-β1 overproduction.
Fibrotic diseases associated with TGF-β1 overproduction can be divided into chronic conditions, such as fibrosis of the kidney, lung and liver, and more acute conditions, such as dermal scarring and restenosis (Chamberlain, J. Cardiovascular Drug Reviews, 19 (4): 329-344). Synthesis and secretion of TGF-β1 by tumor cells can also lead to immune suppression, as seen in patients with aggressive brain or breast tumors (Arteaga, et al. (1993) J. Clin. Invest. 92: 2569-2576). The course of Leishmanial infection in mice is drastically altered by TGF-β1 (Barral-Netto, et al. (1992) Science 257: 545-547). TGF-β1 exacerbated the disease, whereas TGF-β1 antibodies halted the progression of the disease in genetically susceptible mice. Genetically resistant mice became susceptible to Leishmanial infection upon administration of TGF-β1.
The profound effects of TGF-β1 on extracellular matrix deposition have been reviewed (Rocco and Ziyadeh (1991) in Contemporary Issues in Nephrology v. 23, Hormones, autocoids and the kidney. ed. Jay Stein, Churchill Livingston, New York pp. 391-410; Roberts, et al. (1988) Rec. Prog. Hormone Res. 44: 157-197) and include the stimulation of the synthesis and the inhibition of degradation of extracellular matrix components. Since the structure and filtration properties of the glomerulus are largely determined by the extracellular matrix composition of the mesangium and glomerular membrane, it is not surprising that TGF-β1 has profound effects on the kidney. The accumulation of mesangial matrix in proliferative glomerulonephritis (Border, et al. (1990) Kidney Int. 37: 689-695) and diabetic nephropathy (Mauer et al. (1984) J. Clin. Invest. 74: 1143-1155) are clear and dominant pathological features of the diseases. TGF-β1 levels are elevated in human diabetic glomerulosclerosis (advanced neuropathy) (Yamamoto, et al. (1993) Proc. Natl. Acad. Sci. 90: 1814-1818). TGF-β1 is an important mediator in the genesis of renal fibrosis in a number of animal models (Phan, et al. (1990) Kidney Int. 37: 426; Okuda, et al. (1990) J. Clin. Invest. 86: 453). Suppression of experimentally induced glomerulonephritis in rats has been demonstrated by antiserum against TGF-β1 (Border, et al. (1990) Nature 346: 371) and by an extracellular matrix protein, decorin, which can bind TGF-61 (Border, et al. (1992) Nature 360: 361-363).
Excessive TGF-β1 leads to dermal scar-tissue formation. Neutralizing TGF-β1 antibodies injected into the margins of healing wounds in rats have been shown to inhibit scarring without interfering with the rate of wound healing or the tensile strength of the wound (Shah, et al. (1992) Lancet 339: 213-214). At the same time there was reduced angiogenesis, a reduced number of macrophages and monocytes in the wound, and a reduced amount of disorganized collagen fiber deposition in the scar tissue.
TGF-β1 may be a factor in the progressive thickening of the arterial wall which results from the proliferation of smooth muscle cells and deposition of extracellular matrix in the artery after balloon angioplasty. The diameter of the restenosed artery may be reduced by 90% by this thickening, and since most of the reduction in diameter is due to extracellular matrix rather than smooth muscle cell bodies, it may be possible to open these vessels to 50% simply by reducing extensive extracellular matrix deposition. In undamaged pig arteries transfected in vivo with a TGF-β1 gene, TGF-β1 gene expression was associated with both extracellular matrix synthesis and hyperplasia (Nabel, et al. (1993) Proc. Natl. Acad. Sci. USA 90: 10759-10763). The TGF-β1 induced hyperplasia was not as extensive as that induced with PDGF-BB, but the extracellular matrix was more extensive with TGF-β1 transfectants. No extracellular matrix deposition was associated with hyperplasia induced by FGF-1 (a secreted form of FGF) in this gene transfer pig model (Nabel (1993) Nature 362: 844-846).
There are several types of cancer where TGF-β1 produced by the tumor may be deleterious. MATLyLu rat prostate cancer cells (Steiner and Barrack (1992) Mol. Endocrinol. 6: 15-25) and MCF-7 human breast cancer cells (Arteaga, et al. (1993) Cell Growth and Differ. 4: 193-201) became more tumorigenic and metastatic after transfection with a vector expressing the mouse TGF-β1. TGF-β1 has been associated with angiogenesis, metastasis and poor prognosis in human prostate and advanced gastric cancer (Wikstrom et al. (1998) Prostate 37: 19-29; Saito et al. (1999) Cancer 86: 1455-1462). In breast cancer, poor prognosis is associated with elevated TGF-β (Dickson, et al. (1987) Proc. Natl. Acad. Sci. USA 84: 837-841; Kasid, et al. (1987) Cancer Res. 47: 5733-5738; Daly, et al. (1990) J. Cell Biochem. 43: 199-211; Barrett-Lee, et al. (1990) Br. J. Cancer 61: 612-617; King, et al. (1989) J. Steroid Biochem. 34: 133-138; Welch, et al. (1990) Proc. Natl. Acad. Sci. USA 87: 7678-7682; Walker, et al. (1992) Eur. J. Cancer 238: 641-644) and induction of TGF-β1 by tamoxifen treatment (Butta, et al. (1992) Cancer Res. 52: 4261-4264) has been associated with failure of tamoxifen treatment for breast cancer (Thompson, et al. (1991) Br. J. Cancer 63: 609-614). Anti-TGF-β1 antibodies inhibit the growth of MDA-231 human breast cancer cells in athymic mice (Arteaga, et al. (1993) J. Clin. Invest. 92: 2569-2576), a treatment that is correlated with an increase in spleen natural killer cell activity. CHO cells transfected with latent TGF-β1 also showed decreased NK activity and increased tumor growth in nude mice (Wallick, et al. (1990) J. Exp. Med. 172: 1777-1784). Thus, TGF-β secreted by breast tumors may cause an endocrine immune suppression. High plasma concentrations of TGF-β1 have been shown to indicate poor prognosis for advanced breast cancer patients (Anscher, et al. (1993) N. Engl. J. Med. 328: 1592-1598). Patients with high circulating TGF-β before high dose chemotherapy and autologous bone marrow transplantation are at high risk of hepatic veno-occlusive disease (15-50% of all patients with a mortality rate up to 50%) and idiopathic interstitial pneumonitis (40-60% of all patients). The implication of these findings is 1) that elevated plasma levels of TGF-β1 can be used to identify at-risk patients and 2) that reduction of TGF-β1 could decrease the morbidity and mortality of these common treatments for breast cancer patients.
Many malignant cells secrete transforming growth factor β (TGF-β), a potent immunosuppressant, suggesting that TGF-β production may represent a significant tumor escape mechanism from host immunosurveillance. Establishment of a leukocyte sub-population with disrupted TGF-β signaling in the tumor-bearing host offers a potential means for immunotherapy of cancer. A transgenic animal model with disrupted TGF-β signaling in T cells is capable of eradicating a normally lethal TGF-β overexpressing lymphoma tumor, EL4 (Gorelik and Flavell, (2001) Nature Medicine 7 (10): 1118-1122).
Downregulation of TGF-β secretion in tumor cells results in restoration of immunogenicity in the host, while T-cell insensitivity to TGF-β results in accelerated differentiation and autoimmunity, elements of which may be required in order to combat self-antigen-expressing tumors in a tolerated host. The immunosuppressive effects of TGF-β have also been implicated in a subpopulation of HIV patients with lower than predicted immune response based on their CD4/CD8 T cell counts (Garba, et al. J. Immunology (2002) 168: 2247-2254). A TGF-β neutralizing antibody was capable of reversing the effect in culture, indicating that TGF-β signaling inhibitors may have utility in reversing the immune suppression present in this subset of HIV patients.
During the earliest stages of carcinogenesis, TGF-β1 can act as a potent tumor suppressor and may mediate the actions of some chemopreventive agents. However, at some point during the development and progression of malignant neoplasms, tumor cells appear to escape from TGF-β-dependent growth inhibition in parallel with the appearance of bioactive TGF-β in the microenvironment. The dual tumor suppression/tumor promotion roles of TGF-β have been most clearly elucidated in a transgenic system overexpressing TGF-β in keratinocytes. While the transgenics were more resistant to formation of benign skin lesions, the rate of metastatic conversion in the transgenics was dramatically increased (Cui, et al (1996) Cell 86 (4): 531-42). The production of TGF-β1 by malignant cells in primary tumors appears to increase with advancing stages of tumor progression. Studies in many of the major epithelial cancers suggest that the increased production of TGF-β by human cancers occurs as a relatively late event during tumor progression. Further, this tumor-associated TGF-β provides the tumor cells with a selective advantage and promotes tumor progression. The effects of TGF-β1 on cell/cell and cell/stroma interactions result in a greater propensity for invasion and metastasis.
Tumor-associated TGF-β may allow tumor cells to escape from immune surveillance since it is a potent inhibitor of the clonal expansion of activated lymphocytes. TGF-β has also been shown to inhibit the production of angiostatin. Cancer therapeutic modalities, such as radiation therapy and chemotherapy, induce the production of activated TGF-β in the tumor, thereby selecting outgrowth of malignant cells that are resistant to TGF-β growth inhibitory effects. Thus, these anticancer treatments increase the risk and hasten the development of tumors with enhanced growth and invasiveness. In this situation, agents targeting TGF-β-mediated signal transduction might be a very effective therapeutic strategy. The resistance of tumor cells to TGF-β has been shown to negate many of the cytotoxic effects of radiation therapy and chemotherapy, and the treatment-dependent activation of TGF-β in the stroma may even be detrimental as it can make the microenvironment more conducive to tumor progression and contributes to tissue damage leading to fibrosis. The development of a TGF-β signal transduction inhibitors is likely to benefit the treatment of progressed cancer alone and in combination with other therapies.
The compounds are suitable for the treatment of cancer and other disease states influenced by TGF-β by inhibiting TGF-β in a patient in need thereof by administration of said compound(s) to said patient. TGF-β would also be useful against atherosclerosis (T. A. McCaffrey: TGF-ps and TGF-β Receptors in Atherosclerosis: Cytokine and Growth Factor Reviews 2000, 11, 103-114) and Alzheimer's (Masliah, E.; Ho, G.; Wyss-Coray, T.: Functional Role of TGF-β in Alzheimer's Disease Microvascular Injury: Lessons from Trangenic Mice Neurochemistry International 2001, 39, 393-400) diseases.
Another key biochemical mechanism of signal transduction involves the reversible phosphorylation of tyrosine residues on proteins. The phosphorylation state of a protein may affect its conformation and/or enzymatic activity as well as its cellular location. The phosphorylation state of a protein is modified through the reciprocal actions of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) at various specific tyrosine residues.
Protein tyrosine kinases comprise a large family of transmembrane receptor and intracellular enzymes with multiple functional domains. The binding of ligand allosterically transduces a signal across the cell membrane where the cytoplasmic portion of the PTKs initiates a cascade of molecular interactions that disseminate the signal throughout the cell and into the nucleus. Many receptor protein tyrosine kinase (RPTKs), such as epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor (PDGFR) undergo oligomerization upon ligand binding, and the receptors self-phosphorylate (via autophosphorylation or transphosphorylation) on specific tyrosine residues in the cytoplasmic portions of the receptor. Cytoplasmic protein tyrosine kinases (CPTKs), such as Janus kinases (e.g. JAK1, JAK2, TYK2) and Src kinases (e.g. src, lck, fyn), are associated with receptors for cytokines (e.g. IL-2, IL-3, IL-6, erythropoietin) and interferons, and antigen receptors. These receptors also undergo oligomerization and have tyrosine residues that become phosphorylated during activation, but the receptor polypeptides themselves do not possess kinase activity.
Like the PTKs, the protein tyrosine phosphatases (PTPs) comprise a family of transmembrane and cytoplasmic enzymes, possessing at least an approximately 230 amino acid catalytic domain containing a highly conserved active site with a consensus motif. The substrates of PTPs may be PTKs which possess phosphotyrosine residues or the substrates of PTKs.
The levels of tyrosine phosphorylation required for normal cell growth and differentiation at any time are achieved through the coordinated action of PTKs and PTPS. Depending on the cellular context, these two types of enzymes may either antagonize or cooperate with each other during signal transduction. An imbalance between these enzymes may impair normal cell functions leading to metabolic disorders and cellular transformation.
It is also well known, for example, that the overexpression of PTKs, such as HER2, can play a decisive role in the development of cancer and that antibodies capable of blocking the activity of this enzyme can abrogate tumor growth. Blocking the signal transduction capability of tyrosine kinases such as Flk-1 and the PDGF receptor have been shown to block tumor growth in animal models.
It has been found that the compounds according to the invention and salts thereof have very valuable pharmacological properties while being well tolerated. In particular, they exhibit TGF-β receptor I kinase-inhibiting properties.
The compounds according to the invention preferably exhibit an advantageous biological activity, which is easily demonstrated in enzyme-based assays, for example assays as described herein. In such enzyme-based assays, the compounds according to the invention preferably exhibit and cause an inhibiting effect, which is usually documented by IC50 values in a suitable range, preferably in the micromolar range and more preferably in the nanomolar range.
As discussed herein, these signaling pathways are relevant for various diseases. Accordingly, the compounds according to the invention are useful in the prophylaxis and/or treatment of diseases that are dependent on the said signaling pathways by interaction with one or more of the said signaling pathways. The present invention therefore relates to compounds according to the invention as promoters or inhibitors, preferably as inhibitors, of the signaling pathways described herein. The invention therefore preferably relates to compounds according to the invention as promoters or inhibitors, preferably as inhibitors, of the TGF-β signaling pathway.
The present invention furthermore relates to the use of one or more compounds according to the invention in the treatment and/or prophylaxis of diseases, preferably the diseases described herein, that are caused, mediated and/or propagated by an increased TGF-β activity.
The present invention therefore relates to compounds according to the invention as medicaments and/or medicament active ingredients in the treatment and/or prophylaxis of the said diseases and to the use of compounds according to the invention for the preparation of a pharmaceutical for the treatment and/or prophylaxis of the said diseases as well as to a method for the treatment of the said diseases comprising the administration of one or more compounds according to the invention to a patient in need of such an administration.
The host or patient can belong to any mammalian species, for example a primate species, particularly humans; rodents, including mice, rats and hamsters; rabbits; horses, cows, dogs, cats, etc. Animal models are of interest for experimental investigations, providing a model for treatment of human disease.
The susceptibility of a particular cell to treatment with the compounds according to the invention can be determined by in vitro tests. Typically, a culture of the cell is combined with a compound according to the invention at various concentrations for a period of time which is sufficient to allow the active agents to induce cell death or to inhibit migration, usually between about one hour and one week. In vitro testing can be carried out using cultivated cells from a biopsy sample. The viable cells remaining after the treatment are then counted.
The dose varies depending on the specific compound used, the specific disease, the patient status, etc. A therapeutic dose is typically sufficient considerably to reduce the undesired cell population in the target tissue while the viability of the patient is maintained. The treatment is generally continued until a considerable reduction has occurred, for example an at least about 50% reduction in the cell burden, and may be continued until essentially no more undesired cells are detected in the body.
For identification of a signal transduction pathway and for detection of interactions between various signal transduction pathways, various scientists have developed suitable models or model systems, for example cell culture models (for example Khwaja et al., EMBO, 1997, 16, 2783-93) and models of transgenic animals (for example White et al., Oncogene, 2001, 20, 7064-7072). For the determination of certain stages in the signal transduction cascade, interacting compounds can be utilized in order to modulate the signal (for example Stephens et al., Biochemical J., 2000, 351, 95-105). The compounds according to the invention can also be used as reagents for testing kinase-dependent signal transduction pathways in animals and/or cell culture models or in the clinical diseases mentioned in this application.
Measurement of the kinase activity is a technique which is well known to the person skilled in the art. Generic test systems for the determination of the kinase activity using substrates, for example histone (for example Alessi et al., FEBS Lett. 1996, 399, 3, pages 333-338) or the basic myelin protein, are described in the literature (for example Campos-Gonzàlez, R. and Glenney, Jr., J. R. 1992, J. Biol. Chem. 267, page 14535).
For the identification of kinase inhibitors, various assay systems are available. In scintillation proximity assay (Sorg et al., J. of. Biomolecular Screening, 2002, 7, 11-19) and flashplate assay, the radioactive phosphorylation of a protein or peptide as substrate with γATP is measured. In the presence of an inhibitory compound, a decreased radioactive signal, or none at all, is detectable. Furthermore, homogeneous time-resolved fluorescence resonance energy transfer (HTR-FRET) and fluorescence polarisation (FP) technologies are suitable as assay methods (Sills et al., J. of Biomolecular Screening, 2002, 191-214). Other non-radioactive ELISA assay methods use specific phospho-antibodies (phospho-ABs). The phospho-AB binds only the phosphorylated substrate. This binding can be detected by chemiluminescence using a second peroxidase-conjugated anti-sheep antibody.